Augmented reality collaboration system

ABSTRACT

A system comprising: a user device, comprising: sensors configured to sense data related to a physical environment of the user device, displays; hardware processors; and a non- transitory machine-readable storage medium encoded with instructions executable by the hardware processors to: place a virtual object in a 3D scene displayed by the second user device, determine a pose of the user device with respect to the physical location in the physical environment of the user device, and generate an image of virtual content based on the pose of the user device with respect to the placed virtual object, wherein the image of the virtual content is projected by the one or more displays of the user device in a predetermined location relative to the physical location in the physical environment of the user device.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 17/494,256, filed Oct. 5, 2021, entitled “AUGMENTED REALITYCOLLABORATION SYSTEM,” which is a continuation of U.S. patentapplication Ser. No. 17/023,220, filed Sep. 16, 2020, entitled“AUGMENTED REALITY COLLABORATION SYSTEM,” the disclosures thereofincorporated by reference herein in their entirety.

DESCRIPTION OF RELATED ART

The disclosed technology relates generally to augmented reality systems,and more particularly, some embodiments relate to collaboration usingsuch systems.

SUMMARY

A claimed solution rooted in computer technology overcomes problemsspecifically arising in the realm of computer technology.

In general, one aspect disclosed features a system comprising: a systemconfigured to display virtual content, comprising: a user device,comprising: one or more sensors configured to sense data related to aphysical environment of the user device, and one or more displays; oneor more hardware processors; and a non-transitory machine-readablestorage medium encoded with instructions executable by the one or morehardware processors to: place a virtual object in a 3D scene displayedby the second user device in a virtual location that corresponds to aphysical location in the physical environment of the user deviceresponsive to user input received by the user device, determine a poseof the user device with respect to the physical location in the physicalenvironment of the user device, and generate an image of virtual contentbased on the pose of the user device with respect to the placed virtualobject, wherein the image of the virtual content is projected by the oneor more displays of the user device in a predetermined location relativeto the physical location in the physical environment of the user device.

Embodiments of the system may include one or more of the followingfeatures. Some embodiments comprise a second virtual content system,comprising: a structure comprising a plurality of radiation emittersarranged in a predetermined pattern, and a second user device, whereinthe second user device comprises: one or more sensors configured tosense outputs of the plurality of radiation emitters, and one or moredisplays; one or more hardware processors; and a non-transitorymachine-readable storage medium encoded with instructions executable bythe one or more hardware processors to: determine a pose of the seconduser device with respect to the structure based on the sensed outputs ofthe plurality of radiation emitters, and generate a second image of thevirtual content based on the pose of the second user device with respectto the structure, wherein the second image of the virtual content isprojected by the one or more displays of the second user device in apredetermined location relative to the structure. In some embodiments,the first virtual content system is remote from the second virtualcontent system. In some embodiments, the first virtual content system isproximate to the second virtual content system. In some embodiments, theinstructions are further executable by the one or more hardwareprocessors to: generate a virtual proxy of the first user device; andadd the virtual proxy to the second image based on (i) the pose of thefirst user device with respect to the virtual object, wherein the imageis projected by the one or more displays of the second user device. Insome embodiments, the instructions are further executable by the one ormore hardware processors to: generate a virtual proxy of the second userdevice; and add the virtual proxy to the first image based on (i) thepose of the second user device with respect to the structure, and (ii)the pose of the placed virtual object with respect to the structure,wherein the image is projected by the one or more displays of the firstuser device. In some embodiments, the plurality of radiation emitters isconfigured to emit infrared light; the one or more sensors on the seconduser device are configured to sense the output of the plurality ofradiation emitters; and the instructions are further executable by theone or more hardware processors in the second user device to determinethe pose of the second user device with respect to the structure basedon the sensed output of the plurality of radiation emitters. In someembodiments, the instructions are further executable by the one or morehardware processors to perform, responsive to user input received by theuser device, at least one of: selecting the virtual content, andmodifying the virtual content. In some embodiments, the second userdevice may be worn on the head of a user. Some embodiments comprise ahandheld electronic device; wherein the instructions are furtherexecutable by the one or more hardware processors to perform, responsiveto user input received by the handheld electronic device, at least oneof: selecting the virtual content, and modifying the virtual content. Insome embodiments, the second user device further comprises at least oneoptical element which facilitates viewing of the second image integratedwith a view of the physical environment. In some embodiments, thestructure is attached to a physical object. Some embodiments comprise asecond system configured to display virtual content, comprising: asecond user device, comprising: a second set of one or more sensorsconfigured to sense data related to a physical environment of the seconduser device, and a second set of one or more displays; wherein theinstructions are further executable by the one or more hardwareprocessors to: place a second virtual object in 3D scene displayed bythe second user device in a virtual location that corresponds to aphysical location in the physical environment of the second user deviceresponsive to user input received by the second user device, determine apose of the second user device with respect to the physical location inthe physical environment of the second user device, and generate asecond image of the virtual content based on the pose of the second userdevice with respect to the placed virtual object, wherein the secondimage of the virtual content is displayed by the one or more displays ofthe second user device in a predetermined location relative to theplaced second virtual object. In some embodiments, the first virtualcontent system is remote from the second virtual content system. In someembodiments, the first virtual content system is proximate to the secondvirtual content system.

In general, one aspect disclosed features a non-transitorymachine-readable storage medium encoded with instructions executable bythe one or more hardware processors to, for a user device in a systemconfigured to display virtual content: sense a representation of aphysical environment of the user device; place a virtual object in a 3Dscene displayed by the second user device in a virtual location thatcorresponds to a physical location in the physical environment of theuser device responsive to user input received by the user device;determine a pose of the user device with respect to the physicallocation in the physical environment of the user device; and generate animage of virtual content based on the pose of the user device withrespect to the placed virtual object, wherein the image of the virtualcontent is projected by one or more displays of the user device in apredetermined location relative to the physical location in the physicalenvironment of the second user device.

Embodiments of the non-transitory machine-readable storage medium mayinclude one or more of the following features. In some embodiments, theinstructions are further executable by the one or more hardwareprocessors to, for a second user device in a second system configured todisplay the virtual content: sense outputs of a plurality of radiationemitters arranged in a structure in a predetermined pattern; determine apose of the second user device with respect to the structure based onthe sensed outputs of the plurality of radiation emitters, and generatea second image of the virtual content based on the pose of the seconduser device with respect to the structure, wherein the second image ofthe virtual content is projected by one or more displays of the seconduser device in a predetermined location relative to the structure. Insome embodiments, the instructions are further executable by the one ormore hardware processors to: generate a virtual proxy of the first userdevice; and add the virtual proxy to the second image based on the poseof the first user device with respect to the virtual object, wherein theimage is projected by the one or more displays of the second userdevice. In some embodiments, the instructions are further executable bythe one or more hardware processors to: generate a virtual proxy of thesecond user device; and add the virtual proxy to the first image basedon the pose of the second user device with respect to the structure,wherein the image is displayed by the one or more displays of the firstuser device. In some embodiments, the plurality of radiation emitters isconfigured to emit infrared light; the instructions are furtherexecutable by the one or more hardware processors of the second userdevice to: sense the output of the plurality of radiation emitters, anddetermine the pose of the second user device with respect to thestructure based on the sensed output of the plurality of radiationemitters. In some embodiments, the instructions are further executableby the one or more hardware processors to perform, responsive to userinput received by the user device, at least one of: selecting thevirtual content; and modifying the virtual content. wherein second userdevice comprises at least one optical element, which facilitates viewingof the second image integrated with the second user's view of physicalenvironment.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure, in accordance with one or more variousembodiments, is described in detail with reference to the followingfigures. The figures are provided for purposes of illustration only andmerely depict typical or example embodiments.

FIG. 1 illustrates an augmented reality collaboration system featuring aphysical holopad according to some embodiments of the disclosedtechnology.

FIG. 2 illustrates the use of an augmented reality collaboration systemfeaturing a physical holopad in conjunction with a computer-aided design(CAD) system according to some embodiments of the disclosed technology.

FIG. 3 is a perspective view of the interior of a physical holopadaccording to some embodiments of the disclosed technology.

FIG. 4 is a perspective view of a headset according to some embodimentsof the disclosed technology.

FIG. 5 is a perspective view of an add-on device according to someembodiments of the disclosed technology.

FIG. 6 is a perspective view of a user device with the add-on deviceattached according to some embodiments of the disclosed technology.

FIG. 7 illustrates an augmented reality collaboration system featuring avirtual holopad according to some embodiments of the disclosedtechnology.

FIG. 8 illustrates some example networked systems according toembodiments of the disclosed technology.

FIG. 9 is a flowchart of a process of a physical holopad systemaccording to some embodiments of the disclosed technology.

FIG. 10 is a flowchart of a process of a virtual holopad systemaccording to some embodiments of the disclosed technology.

FIG. 11 is a flowchart for a process for providing, to a second holopadsystem user, a virtual proxy of a user in a first holopad system,according to embodiments of the disclosed technology.

FIG. 12 is an example computing component that may be used to implementvarious features of embodiments described in the present disclosure.

The figures are not exhaustive and do not limit the present disclosureto the precise form disclosed.

DETAILED DESCRIPTION

With continued advances in computing and networking technology, computersystems are providing better ways for people to collaborate virtuallywhile collocated or in remote locations. At the same time, augmentedreality systems are providing better ways for people to view and modifythree-dimensional content. However, attempts to combine these systemshave proven unsuccessful. Current systems fail to deliver sufficientvisual quality, generally providing both low image quality and aninsufficient field of view. These systems also generally lack an abilityto provide close-up views, and don't accommodate users wearingeyeglasses. And these systems don't allow users to see each other'seyes, further diminishing the collaborative experience.

Furthermore, these systems provide insufficient input and controlfeatures for users. Current systems are generally complex andergonomically challenging, for example making text entry difficult, andconfronting new users with a steep learning curve. In addition, currentsystems require extensive preparation for use. For example, many ofthese systems require data preparation, software development, gesturerecognition technologies, and/or time-consuming room and surfacescans—and the computing power to perform all of these functions, oftensimultaneously—before and during each use. Finally, many of thesesystems are incompatible with current collaboration systems such asexisting collaborative meeting solutions.

Rising to these challenges, some embodiments of the disclosed technologyprovide augmented reality collaboration systems featuring physicaldevices that designate a projection location for virtual contentdisplayed by the collaboration system, also referred to herein asphysical “holopads.” In these embodiments, images of virtual content aredisplayed to the users in a predetermined location relative to thephysical holopad, such that the virtual content resembles a hologramprojected by the holopad. The users may view and interact with virtualcontent using a variety of user devices, including headsets, tablets,smartphones, controllers, gestures and gesture recognition coupled withvirtual control systems, and the like. Each physical holopad not onlyprovides position and orientation information for the system, but alsoserves as an intuitive physical point of reference for the users. Whileconventional two-dimensional collaboration systems make it clear wherevirtual content will appear, shared holographic experiences can appearanywhere, and therefore don't make it clear to users where to look. Withthe disclosed holopads, the disclosed technology acts as a shared 3Dmonitor, making it clear to users of the collaboration system wherevirtual content will appear, thus facilitating the purpose andeffectiveness of the system. In some embodiments, the disclosedtechnology permits 3D videoconferencing, with a holopad at eachlocation. These embodiments enable geographically-distributed users tofeel as though they are all collaborating around the same table.

In some embodiments, each physical holopad may be a structure thatincludes a plurality of radiation emitters, for example such as infraredemitters, arranged in a known pattern. The holopad may be placed in acentral location about which users may gather in a single location, forexample such as a conference room table. Sensors on each user device maydetect emissions from the emitters to determine the pose of the headsetwith respect to the holopad. As used herein, the “pose” of an objectrepresents its spatial relationship with another object, includingposition and orientation.

In other embodiments, sensors on a user device may determine the pose ofthe headset with respect to the physical holopad using object or imagerecognition technologies. In such embodiments, the physical holopad neednot include radiation emitters.

In any embodiment, determining a pose may include processing outputs ofinertial monitoring units (IMUs) in the user devices. For example, auser device that takes the form of a headset may include an IMU. Sensorssuch as cameras typically allow position fixes at relatively lowfrequencies of around 60 Hz. Conversely, IMUs may provide positionchanges at a very high rate, for example at a frequency of 200 Hz orhigher. The fusion of these two technologies and their relative outputsallows the collaboration system to achieve highly-accurate positionfixes, while also allowing it to make highly-accurate predictions of theuser's future positions.

The system may generate an image of the virtual content for each userdevice based on its pose with respect to the physical holopad. The userdevices may display the images in a predetermined location relative tothe physical holopad. For example, the virtual content may appear to theusers to hover above the holopad as though the holopad were projecting ahologram of the virtual content.

Some embodiments of the disclosed technology provide augmented realitycollaboration systems featuring virtual holopads. In these embodiments,users may view and interact with virtual content using a variety of userdevices, including headsets, tablets, smartphones, and the like, withoutthe use of a physical holopad. Instead of placing a physical structureon a surface, the user may employ the user device and surface trackingsoftware (such as ARKit or ARCore) to place a virtual holopad on thesurface. These embodiments are ideal for environments where a physicalholopad may not be available or convenient, such as a hotel room. Likethe physical holopad, the virtual holopad serves as a visual point ofreference for the user as well as a means for aligning the coordinatesystem of the user's environment with that of remote systems thatinclude a physical or virtual holopad. As with the physical holopad, thesystem generates an image of the virtual content for display on a userdevice in a predetermined location relative to the virtual holopad. Forexample, the virtual content may appear to the users to hover above thevirtual holopad as though the virtual holopad were projecting a hologramof the virtual content. Regardless of user location and whether aphysical or virtual holopad is being used, all users see the virtualcontent in the same position relative to the holopad, thereby thuscreating the perception of the system as presenting a shared3D/holographic monitor.

In some embodiments, one or more of the disclosed augmented realitysystems may be interconnected to share virtual content for communicationor collaboration. For example, the interconnected systems may benetworked, and may include one or more of the physical holopad systemsand one or more of the virtual holopad systems. In such embodiments,each user may have one or more permissions. For example, the permissionsmay include permissions to view or edit the virtual content. The usersmay change permissions during the collaboration, according to user inputand/or specific parameters that may be set on the system at the outsetor during the collaboration session. Any of the systems may be remotefrom one or more other systems. Any of the virtual holopad systems maybe collocated with other virtual or physical holopad systems.

FIG. 1 illustrates an augmented reality collaboration system 100featuring a physical holopad according to some embodiments of thedisclosed technology. Referring to FIG. 1 , the system 100 includes aphysical holopad 102 and a plurality of user devices employed by threeusers 104 a,b,c to view and interact with virtual content 106, which inthis example represents a building. In this example, users 104 a,bemploy headsets 108 a,b to view the virtual content 106, while user 104c employs a tablet 110 to view the virtual content 106.

In the example of FIG. 1 , users 104 b,c are local, and are physicallypresent in the same room as the holopad 102, and user 104 a is remote,in another location, as indicated by broken lines. A virtual proxy ofthe remote user 104 a may be displayed to the local users 104 b,c aspart of the virtual content 106, for example as described below indetail. In the example of FIG. 1 , the virtual proxy represent theheadset 108 a of the remote user 104 a.

As noted above, the pose of each user device with respect to thephysical holopad 102 may be determined by sensing emitters on theholopad, or by object or image recognition. To facilitate use of theemitters, the tablet 110 may include sensors, or may be equipped with anadd-on device that includes the sensors, for example as described below.

The system may include one or more computer systems 116 each featuring amemory and one or more processors executing instructions stored in thememory to generate images of the virtual content 106 for display to theusers 104 on the user devices, which may be tethered to the computersystems 116 for power and communications. For example, the headsets maybe tethered to the computer system, while the mobile devices may run ontheir own batteries and compute power. In some embodiments, some or allof this processing may take place at the user devices, which may bebattery-powered and contain any and all processors and communicationequipment needed to function in the collaboration system. In someembodiments, the user devices may have wired connections to thecomputer, for example to provide high image quality, compute power,and/or electrical power. In some embodiments, the user devices may havewireless connections to the computer, such as Bluetooth, WiFi, and thelike, for example to allow increased mobility of the users 104.

The users 104 may employ their user devices, or a peripheral device thatis directly or indirectly connected to their user devices, to interactwith the virtual content 106. For example, a smartphone may include anapp that provides tools for interacting with the virtual content. In theexample of FIG. 1 , user 104 b is shown using a smartphone 112 b tointeract with the content using a beam 114. In some embodiments, thebeam 114 may be a virtual beam generated by the system and visible onthe user devices. Interaction with the virtual content may includeselection of the virtual content, modification of the virtual content,annotation of the virtual content, and the like.

In some embodiments, the other users 104 a,c may also interact with thevirtual content 106, either sequentially or concurrently. For example,user 104 a may employ a smartphone 112 a to interact with the virtualcontent 106, while user 104 c may employ tablet 110. In someembodiments, the users 104 a,b may employ their headsets 108 a,b tointeract with the virtual content 106. In such embodiments, the headsetsmay include user interfaces including tactile control, gaze control,voice command, and the like. As noted below, in gesture-controlledsystems, the headsets 108 may include sensors for detecting thegestures.

In some embodiments, the disclosed systems may be used in conjunctionwith other systems. For example, the systems may include applicationsfor creating virtual content using 3D data from existing 3D tools suchas computer-aided design (CAD) systems. FIG. 2 illustrates the use of anaugmented reality collaboration system 200 featuring a physical holopadin conjunction with a CAD system according to some embodiments of thedisclosed technology. Referring to FIG. 2 , the system 200 includes aphysical holopad 202 and a headset 208 for viewing virtual content 206,which in this example represents a rocket engine. In this example, thesystem 200 also includes a CAD system 220. The views generated by theCAD system 220 may be coordinated with the views of the virtual content206. For example, manipulation of one view may affect both views, forexample in real time.

While in FIG. 2 the physical holopad 202 is shown as a standalone unit,the disclosed physical holopads may take any physical form, and may beattached to, or integrated with, one or more physical objects. In FIG. 2, three examples are shown. The physical holopad 202 is a cruciformdesign. A physical holopad 210 is attached to, or integrated with, theframe of a computer monitor. A physical holopad 212 is attached to, orintegrated with, a stand 214 for holding the headsets 208.

FIG. 3 is a perspective view of the interior of a physical holopad 300according to some embodiments of the disclosed technology. In theseembodiments, the holopad has a cruciform design and four radiationemitters 302 a,b,c,d disposed within respective arms of the physicalholopad 300. However, as noted above, the disclosed physical holopadsmay take any physical shape. In some embodiments, the emitters 302 arearranged in a predetermined pattern that is known to the system. Thesearrangements facilitate determining poses of the user devices withrespect to the physical holopad 300.

FIG. 4 is a perspective view of a headset 400 according to someembodiments of the disclosed technology. Referring to FIG. 4 , theheadset 400 may include a sensor 402 configured to capture emissions ofthe emitters of the physical holopads. For example, when the emittersare infrared emitters, the sensor 402 may include an infrared cameraconfigured to capture images of the emitters.

The headset 400 may include one or more optical elements. The opticalelement(s) may be implemented as any reflective translucent optic, forexample as shown at 404. For example, the optical element(s) 404 may beimplemented as an off-axis optic, birdbath optic, prismatic optic,planar optic (i.e., a “waveguide”), or the like. In some of theseembodiments, the optical elements are designed to permit othercollocated users to see the eyes of the wearer. The translucent opticcould be user replaceable with reflective opaque optic for a virtualreality experience.

In some embodiments, the optical element 404 may be replaced oraugmented by a display to allow for pass-through augmented reality orvirtual reality experiences. In such embodiments, the display may be aLCD, LED, OLED, or other display, that is positioned in the user devicein front of the user's eyes. In such embodiments, the displayfacilitates viewing the image of the virtual content integrated with thephysical environment. In some of these embodiments, the headset 400includes a camera for capturing images of the physical environment, andthese images are added to the images of virtual content so the wearersees the virtual content integrated with the physical environment. Insuch embodiments, the front of the headset may be opaque.

The headset 400 may include a head attachment mechanism 406. The headattachment mechanism 406 may be implemented in any manner. For example,the head attachment mechanism 406 may be implemented as a headband orthe like. In some embodiments, the optical element 404 is positioned sothe headset 400 provides ample room to accommodate users wearingeyeglasses.

In some embodiments, the user device for viewing the virtual content maybe implemented as a handheld computer, such as a smartphone, tablet, orthe like. In some embodiments, these handheld user devices may includesensors capable of detecting the emitters of the physical holopad. Insome embodiments, where the user devices may not be capable of suchsensing, some embodiments may provide or be configured to accept anadd-on device capable of performing the sensing.

FIG. 5 is a perspective view of an add-on device 500 according to someembodiments of the disclosed technology. Referring to FIG. 5 , theadd-on device 500 may include an attachment device 502 configured toattach the add-on device 500 to a user device. In the example of FIG. 5, the attachment device 502 is implemented as a clamp. However, theattachment device 502 may attach to the user device in any manner.

FIG. 6 is a perspective view of a user device 600 with the add-on device500 attached according to some embodiments of the disclosed technology.In the example of FIG. 6 , the user device is implemented as asmartphone. However, the user device 600 may be any device capable ofperforming the functions described herein.

In some embodiments, the add-on device 500 may be configured tocommunicate wirelessly with the user device 600. For example, the add-ondevice 500 may include a Bluetooth transceiver, NFC device, WiFi device,or the like. In some embodiments, the add-on device 500 may have a wiredcommunication connection to the user device 600. For example, the add-ondevice 500 may have a connector configured to connect to a connector ofthe user device 600. In some embodiments, there is no wired or wirelesscommunications connection directly between add-on device 500 and userdevice 600. Instead, the add-on device 500 may communicate to a computernetwork, to which user device 600 is also connected, for example viathat user device's cellular or internet connection (e.g., via WiFi). Insome embodiments, the add-on device 500 may include an NFC tag to pairthe add-on device 500 and the user device 600 for direct communications.For example, a user may enter a conference room, pick up an add-ondevice 500, which pairs with the user device 600, identifies itself tothe user device 600, which automatically opens up a controller app onthe user device 600.

In some embodiments, the add-on device 500 may have a power sourceindependent of the power source of the user device 600. In someembodiments, the add-on device 500 may be configured to draw power fromthe user device 600. In some embodiments, the add-on device 500 may beconfigured to provide power to the user device 600. All combinations ofthe described configurations are contemplated.

FIG. 7 illustrates an augmented reality collaboration system 700featuring a virtual holopad 702 according to some embodiments of thedisclosed technology. Referring to FIG. 7 , the system 700 includes auser device that a user can use to view and interact with virtualcontent 706, which in this example represents a rocket engine. In theexample of FIG. 7 , the user device is implemented as a tablet 710.However, the user device may be any device capable of performing thefunctions described herein. For example, the user device may beimplemented as a headset, smartphone, laptop, and the like.

A user may employ the tablet 710 to place a virtual object in a 3D scenedisplayed by the tablet 710 in a virtual location that corresponds to aphysical location in the user's physical environment. In this example,the user has placed the virtual holopad 702 in the virtual locationcorresponding to the surface of table 720. Of course, the user may placethe virtual holopad 702 in virtual locations corresponding to othersurfaces in the user's physical environment instead.

As with the physical holopad, the virtual holopad serves as a point ofreference for the user. In some embodiments, the system may determinethe pose of the tablet 710 with respect to the physical surfaceindicated by the virtual holopad 702. For example, an applicationexecuting on the tablet 710 may use one or more sensors to scan andtrack surfaces in the physical environment, and to determine thephysical location indicated by the virtual holopad with respect to thetablet 710.

The system generates an image of the virtual content 706 and the virtualholopad 702 based on the pose of the tablet 710 with respect to thesurface of table 720 selected by the user and enabled by surfacetracking software implemented by the tablet 710. The tablet 710 may thendisplay the image in a predetermined location relative to the virtualholopad 702. For example, the virtual content may appear to the user tohover above the virtual holopad as though the holopad were projecting ahologram of the virtual content. The image may include an image of thevirtual holopad 702. The image may include an image of the physicalenvironment, as shown in FIG. 7 , where the image includes an image ofthe table 720.

FIG. 8 illustrates some example networked systems according toembodiments of the disclosed technology. One or more of the systems mayinclude a wireless router to connect one or more components of thesystem. The wireless router may employ any wireless technology, forexample including WiGig, WiFi6, 5G mmWave, and the like.

Several example system configurations are shown, interconnected by anetwork 812. However, it should be appreciated that other systemconfigurations may be employed and interconnected in any number. Whilethe user devices are illustrated as headsets, any sort of user devicemay be employed. A configuration including two users and a physicalholopad in one room is shown at 804. In configuration 804, both usersare viewing the same virtual content. A configuration including twousers and a first physical holopad in one room, and one user and asecond physical holopad in a second room, is shown at 806. Inconfiguration 806, all three users are viewing the same virtual content.A configuration including one user and a first physical holopad in oneroom, and one user and a second physical holopad in a second room, isshown at 808. In configuration 808, both users are viewing the samevirtual content. A configuration including one user and a virtualholopad, indicated by a broken line, in one room is shown at 810.

FIG. 9 is a flowchart of a process 900 of a physical holopad systemaccording to some embodiments of the disclosed technology. For example,the process 900 may be performed by the physical holopad system 100 ofFIG. 1 . For clarity, the process 900 is described for one user device.However, the process 900 may be performed for each user device in aphysical holopad system.

Referring to FIG. 9 , the process 900 may include sensing outputs of aplurality of radiation emitters disposed in a structure, at 902. In theexample of FIG. 1 , each of the headsets 108 may include one or moresensors, for example such as the sensor 402 of FIG. 4 . Ingesture-controlled systems, the headsets 108 may include additionalsensors for detecting the gestures. Each user device may include asensor, for example integrated in the user device or as part of anadd-on device such as the add-on device 500 of FIG. 5 . The emitters maybe infrared emitters, and the sensor may be an infrared camera thatcaptures an image of the infrared emitters.

Referring again to FIG. 9 , the process 900 may include determining apose of the user device with respect to the structure based on thesensed outputs of the radiation emitters and outputs of the IMU, at 904.Continuing with the example of FIG. 1 , the computer system(s) 116 maydetermine a pose of the user device 108 with respect to the physicalholopad 102.

Referring again to FIG. 9 , the process 900 may include generating animage of virtual content based on the pose of the user device withrespect to the structure, at 906. Continuing with the example of FIG. 1, the computer system(s) 116 may generate an image of the virtualcontent 106 for the user device 108 based on the pose of the user device108 with respect to the holopad 102.

Each user device may have a different pose with respect to the holopad102. Therefore each image may be different, and may present the virtualcontent as viewed from the respective pose. The system may fix theorientation of the virtual content with respect to the holopad 102, andmay update the images frequently. For example, the images may berefreshed at a high rate using complex algorithms such as fused cameraand inertial sensors with prediction based on head motion models.Therefore, the virtual content may appear to remain stationary, so thatthe users may move about the room to view the virtual content fromdifferent perspectives.

For user devices that permit stereoscopic viewing, the system maygenerate a pair of images. Such user devices may display the pair ofimages concurrently as a stereoscopic image of the virtual content.

Referring again to FIG. 9 , the process 900 may include displaying animage on an optical element of the user device in a predeterminedlocation relative to the structure, at 908. Continuing the example ofFIG. 1 , the computer system(s) 116 may transmit the image to the userdevice, and responsive to receiving the image, the user device maydisplay the image on its display or optical element. The process 900 mayrepeat, providing a seamless viewing experience to the user.

FIG. 10 is a flowchart of a process 1000 of a virtual holopad systemaccording to some embodiments of the disclosed technology. For example,the process 1000 may be performed by the virtual holopad system 700 ofFIG. 7 . For clarity, the process 1000 is described for one user device.However, the process 1000 may be performed for each user device in thevirtual holopad system.

Referring to FIG. 10 , the process 1000 may include capturing datarelated to the physical environment, at 1002. In the example of FIG. 7 ,the tablet 710 may include a sensor for capturing the image. The sensormay be implemented as a camera, depth sensor, or the like, orcombinations thereof.

Referring again to FIG. 10 , In the example of FIG. 7 , the tablet 710may include a sensor for capturing the image. The sensor may beimplemented as a camera, depth sensor, or the like, or combinationsthereof.

Referring again to FIG. 10 , the process 1000 may include determining apose of the user device with respect to the physical environment, at1003, and placing a virtual object in a 3D scene displayed by the userdevice in a virtual location that corresponds to a physical location inthe physical environment responsive to user input received by the userdevice, at 1004. Continuing with the example of FIG. 7 , a user mayemploy the tablet 710 to place the virtual holopad 702 on the table 720.The virtual holopad 702 then appears to remain in that location even asthe tablet 710 is moved about by the user.

Referring again to FIG. 10 , the process 1000 may include determining apose of the user device with respect to the physical location of theplaced virtual object, at 1006. Continuing with the example of FIG. 7 ,the tablet 710 may determine a pose of the tablet 710 with respect tothe virtual holopad 702. That is, the tablet 710 may determine a pose ofthe tablet 710 with respect to the physical location on the table 720where the virtual holopad 702 has been placed in the virtualenvironment. This pose may be determined in any suitable manner. Forexample, the pose may be determined by a commercially-availableapplication such as ARKit or ARCore, which creates a virtual map of thesurfaces and other notable physical characteristics of the user'sphysical environment that the application is programmed to recognize.

Referring again to FIG. 10 , the process 1000 may include generating animage of virtual content based on the pose of the user device withrespect to the physical location of the virtual object, at 1008.Continuing with the example of FIG. 7 , the tablet 710 may generate animage of the virtual content 706 for the user based on the pose of thetablet 710 with respect to the physical location that corresponds to theuser's placement of the virtual holopad. The image presents the virtualcontent 706 as viewed from that pose. The system may fix the orientationof the virtual content with respect to the virtual holopad 702, and mayupdate the images frequently. Therefore, the virtual content appears toremain stationary, so that the user may move about the room to view thevirtual content from different perspectives.

For user devices that permit stereoscopic viewing, the system maygenerate a pair of images. Such user devices may display the pair ofimages concurrently as a stereoscopic image of the virtual content.

Referring again to FIG. 10 , the process 1000 may include displaying animage on a display or optical element of the user device in apredetermined location relative to the physical location of the placedvirtual object, at 1010. Continuing the example of FIG. 7 , the imagemay be displayed on the tablet 710 as illustrated in FIG. 7 . In otherembodiments, the image may be displayed on other user devices such asheadsets, smartphones, laptops, and the like. The process 1000 mayrepeat, providing a seamless viewing experience to the user.

In some embodiments, users may share their images of the virtual contentwith other users. For example, while explaining a particular view of thevirtual content, a presenter may share the presenter's view of thevirtual content so other users see the same view.

In some embodiments, each networked system may include, in imagesprovided to its local users, representations of users and/or userdevices in other systems. These representations, referred to herein as“virtual proxies,” may take any form. For example, a virtual proxy of auser may represent only the user devices currently employed by thatuser. However, the virtual proxies may be represented in any way. Insome embodiments, movements of the users may be tracked to provide morerealistic virtual proxies. For example, the systems may track movementof a user's head, hand, body, eyes, and the like.

FIG. 11 is a flowchart for a process 1100 for providing, to a secondholopad system user, a virtual proxy of a user in a first holopadsystem, according to embodiments of the disclosed technology. Either ofthe first and second holopad systems may be a virtual holopad system ora physical holopad system.

Referring to FIG. 11 , the process 1100 may include generating a virtualproxy of a user device in the physical holopad system, at 1102. Thevirtual proxy may include one or more three-dimensional objects. Thevirtual proxy may represent one or more user devices, the user, acontrol device being used by the user, or any combination thereof.

Referring again to FIG. 11 , the process 1100 may include adding thevirtual proxy to an image of virtual content for the second holopadsystem, at 1104. In some embodiments, the virtual proxy is added to theimage of virtual content based on the pose of the user device withrespect to the holopad in the first holopad system. This use of posepreserves the spatial relationship between the user and the virtualcontent, so that relationship is replicated with the virtual proxy inthe second holopad system.

In some embodiments, the first holopad system may add the virtual proxyto the images of the virtual content, and provide those images to thesecond holopad system. Alternatively, the first holopad system maytransmit, to the second holopad system, the virtual proxy, orinformation representing the virtual proxy, along with informationdescribing the pose of the user device with respect to the structure,thereby enabling the second holopad system to generate an image of thevirtual content that includes the virtual proxy.

Finally, the process 1100 may include displaying the image in the secondholopad system, at 1106. For example, the image may be displayed on oneor more user devices employed by users of the second holopad system toview the virtual content.

In some embodiments, the disclosed systems may cooperate to present thevirtual content in the same geographical orientation at each system. Insuch embodiments, each system may use compass directions to orient thevirtual content. For example, virtual content representing a buildingmay be oriented so the north side of the building faces north. In suchembodiments, the physical holopad may include a compass. In someembodiments, the compass may be visible to the users so the users canrotate the holopad to face north. In some embodiments, the compass mayinclude a transmitter to transmit direction information to the devicesthat generate the images of the virtual content, which may employ thatdirection information to rotate the virtual content accordingly. In someembodiments, the physical holopad may include a design element thatindicates how the holopad should be placed in a room to provide adesired perspective of the virtual content to an audience. For example,the top of the holopad may have an arrow with the word “Audience” toindicate proper orientation.

These techniques may be employed for the positioning of the virtualproxies as well. For example, when a user of a first holopad is locatedto the west of the virtual content, the virtual proxy may be presentedin the second holopad system to the west of the virtual content. In somecase, users in multiple systems may occupy the same position relative tothe virtual content. Superimposing virtual proxies of these users couldbe disconcerting to users. Therefore, in some embodiments, the systemmay display the virtual proxies such that they don't appear on top ofeach other.

It may be desirable to match the lighting conditions of the virtualcontent and virtual proxies with the lighting conditions where thevirtual content will be shown. Therefore, in some embodiments, thephysical holopad and/or user devices may include a camera for detectingambient lighting conditions. The camera may have a wide field of view,for example having a fisheye lens. The computing system(s) and/ordevices generating the images of the virtual content may then adjust thelighting of the virtual content accordingly.

FIG. 12 depicts a block diagram of an example computer system 1200 inwhich embodiments described herein may be implemented. The computersystem 1200 includes a bus 1202 or other communication mechanism forcommunicating information, one or more hardware processors 1204 coupledwith bus 1202 for processing information. Hardware processor(s) 1204 maybe, for example, one or more general purpose microprocessors.

The computer system 1200 also includes a main memory 1206, such as arandom access memory (RAM), cache and/or other dynamic storage devices,coupled to bus 1202 for storing information and instructions to beexecuted by processor 1204. Main memory 1206 also may be used forstoring temporary variables or other intermediate information duringexecution of instructions to be executed by processor 1204. Suchinstructions, when stored in storage media accessible to processor 1204,render computer system 1200 into a special-purpose machine that iscustomized to perform the operations specified in the instructions.

The computer system 1200 further includes a read only memory (ROM) 1208or other static storage device coupled to bus 1202 for storing staticinformation and instructions for processor 1204. A storage device 1210,such as a magnetic disk, optical disk, or USB thumb drive (Flash drive),etc., is provided and coupled to bus 1202 for storing information andinstructions.

The computer system 1200 may be coupled via bus 1202 to a display 1212,such as a liquid crystal display (LCD) (or touch screen), for displayinginformation to a computer user. An input device 1214, includingalphanumeric and other keys, is coupled to bus 1202 for communicatinginformation and command selections to processor 1204. Another type ofuser input device is cursor control 1216, such as a mouse, a trackball,or cursor direction keys for communicating direction information andcommand selections to processor 1204 and for controlling cursor movementon display 1212. In some embodiments, the same direction information andcommand selections as cursor control may be implemented via receivingtouches on a touch screen without a cursor.

The computing system 1200 may include a user interface module toimplement a GUI that may be stored in a mass storage device asexecutable software codes that are executed by the computing device(s).This and other modules may include, by way of example, components, suchas software components, object-oriented software components, classcomponents and task components, processes, functions, attributes,procedures, subroutines, segments of program code, drivers, firmware,microcode, circuitry, data, databases, data structures, tables, arrays,and variables.

In general, the word “component,” “engine,” “system,” “database,” datastore,” and the like, as used herein, can refer to logic embodied inhardware or firmware, or to a collection of software instructions,possibly having entry and exit points, written in a programminglanguage, such as, for example, Java, C, C++, and Python. A softwarecomponent may be compiled and linked into an executable program,installed in a dynamic link library, or may be written in an interpretedprogramming language such as, for example, BASIC, Perl, or Python. Itwill be appreciated that software components may be callable from othercomponents or from themselves, and/or may be invoked in response todetected events or interrupts. Software components configured forexecution on computing devices may be provided on a computer readablemedium, such as a compact disc, digital video disc, flash drive,magnetic disc, or any other tangible medium, or as a digital download(and may be originally stored in a compressed or installable format thatrequires installation, decompression or decryption prior to execution).Such software code may be stored, partially or fully, on a memory deviceof the executing computing device, for execution by the computingdevice. Software instructions may be embedded in firmware, such as anEPROM. It will be further appreciated that hardware components may becomprised of connected logic units, such as gates and flip-flops, and/ormay be comprised of programmable units, such as programmable gate arraysor processors.

The computer system 1200 may implement the techniques described hereinusing customized hard-wired logic, one or more ASICs or FPGAs, firmwareand/or program logic which in combination with the computer systemcauses or programs computer system 1200 to be a special-purpose machine.According to one embodiment, the techniques herein are performed bycomputer system 1200 in response to processor(s) 1204 executing one ormore sequences of one or more instructions contained in main memory1206. Such instructions may be read into main memory 1206 from anotherstorage medium, such as storage device 1210. Execution of the sequencesof instructions contained in main memory 1206 causes processor(s) 1204to perform the process steps described herein. In alternativeembodiments, hard-wired circuitry may be used in place of or incombination with software instructions.

The term “non-transitory media,” and similar terms, as used hereinrefers to any media that store data and/or instructions that cause amachine to operate in a specific fashion. Such non-transitory media maycomprise non-volatile media and/or volatile media. Non-volatile mediaincludes, for example, optical or magnetic disks, such as storage device1210. Volatile media includes dynamic memory, such as main memory 1206.Common forms of non-transitory media include, for example, a floppydisk, a flexible disk, hard disk, solid state drive, magnetic tape, orany other magnetic data storage medium, a CD-ROM, any other optical datastorage medium, any physical medium with patterns of holes, a RAM, aPROM, and EPROM, a FLASH-EPROM, NVRAM, any other memory chip orcartridge, and networked versions of the same.

Non-transitory media is distinct from but may be used in conjunctionwith transmission media. Transmission media participates in transferringinformation between non-transitory media. For example, transmissionmedia includes coaxial cables, copper wire and fiber optics, includingthe wires that comprise bus 1202. Transmission media can also take theform of acoustic or light waves, such as those generated duringradio-wave and infra-red data communications.

The computer system 1200 also includes a communication interface 1218coupled to bus 1202. Network interface 1218 provides a two-way datacommunication coupling to one or more network links that are connectedto one or more local networks. For example, communication interface 1218may be an integrated services digital network (ISDN) card, cable modem,satellite modem, or a modem to provide a data communication connectionto a corresponding type of telephone line. As another example, networkinterface 1218 may be a local area network (LAN) card to provide a datacommunication connection to a compatible LAN (or a WAN component tocommunicate with a WAN). Wireless links may also be implemented. In anysuch implementation, network interface 1218 sends and receiveselectrical, electromagnetic or optical signals that carry digital datastreams representing various types of information.

A network link typically provides data communication through one or morenetworks to other data devices. For example, a network link may providea connection through local network to a host computer or to dataequipment operated by an Internet Service Provider (ISP). The ISP inturn provides data communication services through the world wide packetdata communication network now commonly referred to as the “Internet.”Local network and Internet both use electrical, electromagnetic oroptical signals that carry digital data streams. The signals through thevarious networks and the signals on network link and throughcommunication interface 1218, which carry the digital data to and fromcomputer system 1200, are example forms of transmission media.

The computer system 1200 can send messages and receive data, includingprogram code, through the network(s), network link and communicationinterface 1218. In the Internet example, a server might transmit arequested code for an application program through the Internet, the ISP,the local network and the communication interface 1218.

The received code may be executed by processor 1204 as it is received,and/or stored in storage device 1210, or other non-volatile storage forlater execution.

Each of the processes, methods, and algorithms described in thepreceding sections may be embodied in, and fully or partially automatedby, code components executed by one or more computer systems or computerprocessors comprising computer hardware. The one or more computersystems or computer processors may also operate to support performanceof the relevant operations in a “cloud computing” environment or as a“software as a service” (SaaS). The processes and algorithms may beimplemented partially or wholly in application-specific circuitry. Thevarious features and processes described above may be used independentlyof one another, or may be combined in various ways. Differentcombinations and sub-combinations are intended to fall within the scopeof this disclosure, and certain method or process blocks may be omittedin some implementations. The methods and processes described herein arealso not limited to any particular sequence, and the blocks or statesrelating thereto can be performed in other sequences that areappropriate, or may be performed in parallel, or in some other manner.Blocks or states may be added to or removed from the disclosed exampleembodiments. The performance of certain of the operations or processesmay be distributed among computer systems or computers processors, notonly residing within a single machine, but deployed across a number ofmachines.

As used herein, a circuit might be implemented utilizing any form ofhardware, or a combination of hardware and software. For example, one ormore processors, controllers, ASICs, PLAs, PALs, CPLDs, FPGAs, logicalcomponents, software routines or other mechanisms might be implementedto make up a circuit. In implementation, the various circuits describedherein might be implemented as discrete circuits or the functions andfeatures described can be shared in part or in total among one or morecircuits. Even though various features or elements of functionality maybe individually described or claimed as separate circuits, thesefeatures and functionality can be shared among one or more commoncircuits, and such description shall not require or imply that separatecircuits are required to implement such features or functionality. Wherea circuit is implemented in whole or in part using software, suchsoftware can be implemented to operate with a computing or processingsystem capable of carrying out the functionality described with respectthereto, such as computer system 1200.

As used herein, the term “or” may be construed in either an inclusive orexclusive sense. Moreover, the description of resources, operations, orstructures in the singular shall not be read to exclude the plural.Conditional language, such as, among others, “can,” “could,” “might,” or“may,” unless specifically stated otherwise, or otherwise understoodwithin the context as used, is generally intended to convey that certainembodiments include, while other embodiments do not include, certainfeatures, elements and/or steps.

Terms and phrases used in this document, and variations thereof, unlessotherwise expressly stated, should be construed as open ended as opposedto limiting. Adjectives such as “conventional,” “traditional,” “normal,”“standard,” “known,” and terms of similar meaning should not beconstrued as limiting the item described to a given time period or to anitem available as of a given time, but instead should be read toencompass conventional, traditional, normal, or standard technology thatmay be available or known now or at any time in the future. The presenceof broadening words and phrases such as “one or more,” “at least,” “butnot limited to” or other like phrases in some instances shall not beread to mean that the narrower case is intended or required in instanceswhere such broadening phrases may be absent.

What is claimed is:
 1. A system comprising: a first virtual contentsystem configured to display virtual content, the first virtual contentsystem comprising: a first structure comprising a first plurality ofradiation emitters arranged in a first predetermined pattern, and afirst user device, wherein the first user device comprises: one or morefirst sensors configured to sense outputs of the first plurality ofradiation emitters, and one or more first displays; one or more firsthardware processors; and a first non-transitory machine-readable storagemedium encoded with first instructions executable by the one or morefirst hardware processors to: determine a pose of the first user devicewith respect to the first structure based on the sensed outputs of thefirst plurality of radiation emitters, generate a first image of thevirtual content based on the pose of the first user device with respectto the structure, wherein the first image of the virtual content isprojected by the one or more first displays of the first user device ina predetermined location relative to the first structure; a secondvirtual content system configured to display virtual content, the secondvirtual content system comprising: a second structure comprising asecond plurality of radiation emitters arranged in a secondpredetermined pattern, and a second user device, wherein the second userdevice comprises: one or more second sensors configured to sense outputsof the plurality of radiation emitters, and one or more second displays;one or more second hardware processors; and a second non-transitorymachine-readable storage medium encoded with second instructionsexecutable by the one or more second hardware processors to: determine apose of the second user device with respect to the second structurebased on the sensed outputs of the second plurality of radiationemitters, generate a second image of the virtual content based on thepose of the second user device with respect to the second structure,wherein the second image of the virtual content is projected by the oneor more second displays of the second user device in a secondpredetermined location relative to the second structure.
 2. The systemof claim 1, wherein: the first virtual content system is proximate tothe second virtual content system.
 3. The system of claim 1, wherein:the first virtual content system is remote from the second virtualcontent system.
 4. The system of claim 1, wherein the instructions arefurther executable by the one or more first hardware processors to:generate a virtual proxy of the second user device; and add the virtualproxy of the second user device to the first image based on the pose ofthe second user device with respect to the second structure, wherein theimage is projected by the one or more first displays of the first userdevice.
 5. The system of claim 1, wherein: the first plurality ofradiation emitters is configured to emit infrared light; the one or morefirst sensors on the first user device are configured to sense theoutput of the first plurality of radiation emitters; and theinstructions are further executable by the one or more first hardwareprocessors in the first user device to determine the pose of the firstuser device with respect to the first structure based on the sensedoutput of the plurality of radiation emitters.
 6. The system of claim 1,wherein the instructions are further executable by the one or more firsthardware processors to perform, responsive to user input received by thefirst user device, at least one of: select the virtual content, andmodify the virtual content.
 7. The system of claim 1, furthercomprising: a handheld electronic device; wherein the instructions arefurther executable by the one or more first hardware processors toperform, responsive to user input received by the handheld electronicdevice, at least one of: select the virtual content, and modify thevirtual content.
 8. One or more non-transitory machine-readable storagemedia encoded with instructions, wherein: the instructions areexecutable by one or more hardware processors to, for a first userdevice in a first system configured to display virtual content: senseoutputs of a first plurality of radiation emitters arranged in a firststructure in a first predetermined pattern, determine a pose of thefirst user device with respect to the first structure based on thesensed outputs of the first plurality of radiation emitters, andgenerate a first image of the virtual content based on the pose of thefirst user device with respect to the first structure, wherein the firstimage of the virtual content is projected by one or more displays of thefirst user device in a predetermined location relative to the firststructure; and the instructions are further executable by the one ormore hardware processors to, for a second user device in a secondvirtual content system configured to display virtual content: senseoutputs of a second plurality of radiation emitters arranged in a secondstructure in a second predetermined pattern, determine a pose of thesecond user device with respect to the second structure based on thesensed outputs of the second plurality of radiation emitters, andgenerate a second image of the virtual content based on the pose of thesecond user device with respect to the second structure, wherein thesecond image of the virtual content is projected by one or more displaysof the second user device in a predetermined location relative to thesecond structure.
 9. The non-transitory machine-readable storage mediaof claim 8, wherein: the first virtual content system is proximate tothe second virtual content system.
 10. The non-transitorymachine-readable storage media of claim 8, wherein: the first virtualcontent system is remote from the second virtual content system.
 11. Thenon-transitory machine-readable storage media of claim 8, wherein theinstructions are further executable by the one or more hardwareprocessors to: generate a virtual proxy of the second user device; andadd the virtual proxy of the second user device to the first image basedon the pose of the second user device with respect to the secondstructure, wherein the image is projected by the one or more firstdisplays of the first user device.
 12. The non-transitorymachine-readable storage media of claim 8, wherein: the first pluralityof radiation emitters is configured to emit infrared light; the one ormore first sensors on the first user device are configured to sense theoutput of the plurality of first radiation emitters; and theinstructions are further executable by the one or more hardwareprocessors to determine the pose of the first user device with respectto the first structure based on the sensed output of the first pluralityof radiation emitters.
 13. The non-transitory machine-readable storagemedia of claim 8, wherein the instructions are further executable by theone or more hardware processors to perform, responsive to user inputreceived by the first user device, at least one of: select the virtualcontent, and modify the virtual content.
 14. The non-transitorymachine-readable storage media of claim 8, wherein the instructions arefurther executable by the one or more first hardware processors toperform, responsive to user input received by a handheld electronicdevice, at least one of: select the virtual content, and modify thevirtual content.
 15. A method, comprising: in a first system configuredto display virtual content: sensing outputs of a first plurality ofradiation emitters arranged in a first structure in a firstpredetermined pattern, determining a pose of the first user device withrespect to the first structure based on the sensed outputs of the firstplurality of radiation emitters, generating a first image of the virtualcontent based on the pose of the first user device with respect to thefirst structure, and projecting the first image of the virtual contenton one or more displays of the first user device in a predeterminedlocation relative to the first structure; and in a second virtualcontent system configured to display virtual content: sensing outputs ofa second plurality of radiation emitters arranged in a second structurein a second predetermined pattern, determining a pose of the second userdevice with respect to the second structure based on the sensed outputsof the second plurality of radiation emitters, generating a second imageof the virtual content based on the pose of the second user device withrespect to the second structure, and projecting the second image of thevirtual content on one or more displays of the second user device in apredetermined location relative to the second structure.
 16. The methodof claim 15, wherein: the first virtual content system is proximate tothe second virtual content system.
 17. The method of claim 15, wherein:the first virtual content system is remote from the second virtualcontent system.
 18. The method of claim 15, further comprising:generating a virtual proxy of the second user device; and adding thevirtual proxy of the second user device to the first image based on thepose of the second user device with respect to the second structure,wherein the image is projected by the one or more first displays of thefirst user device.
 19. The method of claim 15, wherein: the firstplurality of radiation emitters is configured to emit infrared light;the one or more first sensors on the first user device are configured tosense the output of the plurality of radiation emitters; and theinstructions are further executable by the one or more hardwareprocessors to determine the pose of the first user device with respectto the first structure based on the sensed output of the plurality ofradiation emitters.
 20. The method of claim 15, further comprising:responsive to user input received by the first user device, at least oneof: selecting the virtual content, and modifying the virtual content.